If you’re restoring an old home, you may find yourself replacing a slate roof. Slate is an extremely durable material, and a roof tiled with slate can last hundreds of years. They are on many historic homes throughout the northeast united states. Some slate roofs have been known to last up to 200 years.

Slate gives a very distinctive look to a home. This is because of the variety of colors and artistic skills used by roofers in previous centuries. History buffs love slate roofs for their multi-colored patterns and aesthetically pleasing tile arrangements. Often, you will see the year of the home’s construction proudly displayed in the slate roof.

Because of its unique history in America and distinctive appearance, the National Parks Service even has a website dedicated to the history and preservation of slate roofs. They recommend repairing a slate roof whenever possible to preserve the homes’ historic value.

What is Slate?

Slate is a fine-grained layered rock. The layering allows cleaving of thicknesses, which means that slaters can make thin, flat sheets relatively quickly and easily. It is also resistant to water, with a water absorption index of less than 0.4 percent, making slate stone virtually waterproof. It also resists damage by ice, since so little water can enter the stone to freeze. These qualities make slate a nearly perfect roofing material.

There are many slate deposits around the world, but in the U.S. most slate mining has been in Vermont, New York, Maine, Maryland, Virginia and Pennsylvanian. Pennsylvania Slate is currently quarried in the U.S. in Vermont and Pennsylvania

Historical Significance of the Slate Roof

Colonists discovered slate in the Northeast region of the U.S. as early as 1625, and used slate roofs in Boston in 1654 and in Philadelphia in 1699. However, some years passed before the commercial development of slate. Until the early 1800s, many builders imported slate from Wales.

Newly opened quarries increased the production of slate tile after the Civil War. Soon, the material boomed as a favorite throughout the Victorian Era and into the 20th century. Slate was the most common roofing material in the Northeastern US from the mid 1800s until the early 1900s. Most homes built during those years in that region will have a slate roof. Furthermore, it’s likely the slate roof will need to be replaced, perhaps for the first time.

Home builders for modern American homes commonly roofed with asphalt shingles following the Second World War. This is still the most common practice today. Slate can be expensive, and the skills needed to install a slate roof are no longer as common.

Advantages and Disadvantages of a Slate Roof

There are currently no building codes that require the replacement of a slate roof with slate. Slate roof tiles are more expensive, however, their durability is beyond question, as is their ability to preserve a home’s historical integrity.

The advantages of slate tile.

Longevity: A slate roof, if properly installed can last up to 200 years.

Appearance: Tile makers manufacture slates from beautiful natural stone that comes in a number of colors. These include green, purple, red, gray, black, and mottled versions. Expert slaters can also repair or replace the homes original artistic design.

Durability: Slate tiles are practically waterproof and freeze-proof. They are also fireproof.

Environmentally Friendly: Because it’s lasts for centuries, there is less need to manufacture more slate tile. It also reduces the need for asphalt tile, which accounts for nearly 5 percent of landfill use from roofing materials.

The disadvantages of slate roofs.

Difficult to Install: Only experts slaters should install a new slate roof. There is no formal education for slating in the U.S., and most roofing contractors don’t know how to install them properly. A DIY homeowner would also find the process beyond their skills and resources.

Weight: Because you’re putting stone tiles on your roof, you’ll need to get a structural engineer to verify that the home is still capable of support that weight.

Fragility: Because slate tiles are fragile, you’ll need to be careful with any future roof work that might require someone stepping on the tiles.

Cost: Most relevant, a slate roof is simply more expensive, partially due to the factors above.

When all is said and done, a homeowner may pay five times as much for a new slate roof than they’ll pay for a new asphalt roof. However it may last 10 times as long. And in the case of historical accuracy, homeowners should consider future plans. The payoff down the line in authenticity could possible make a big difference in resale value.

Featured Image: CC0 Creative Commons by Kellsboro via Flickr

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